The Allwinner H616 and variants have a new display engine revision
(DE33).

The mixer configuration registers are significantly different to the DE3
and DE2 revisions, being split into separate top and display blocks,
therefore a fallback for the mixer compatible is not provided.

Note that the DE33 mixer requires 3 register blocks instead of 1. The maxItems
value for registers is therefore conditionally removed for the H616 and
replaced with the block names from the vendor BSP kernel.

Add a display engine mixer binding for the DE33.

Signed-off-by: Ryan Walklin <redacted>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Chen-Yu Tsai <redacted>
Signed-off-by: Chris Morgan <redacted>

---
Changelog v2..v3:
- Separate content into three patches for three separate subsystems

Changelog v5..v6:
- increase reg maxItems to 3 and add conditional for h616-de33

- Increase reg maxItems to 3.

Changelog v9..v10:
- Use named register blocks rather than by count as names are available from the Allwinner BSP kernel.
---
 .../allwinner,sun8i-a83t-de2-mixer.yaml       | 34 +++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/allwinner,sun8i-a83t-de2-mixer.yaml b/Documentation/devicetree/bindings/display/allwinner,sun8i-a83t-de2-mixer.yaml
index b75c1ec686ad..cbd18fd83e52 100644
--- a/Documentation/devicetree/bindings/display/allwinner,sun8i-a83t-de2-mixer.yaml
+++ b/Documentation/devicetree/bindings/display/allwinner,sun8i-a83t-de2-mixer.yaml

@@ -24,9 +24,11 @@ properties:
       - allwinner,sun50i-a64-de2-mixer-0
       - allwinner,sun50i-a64-de2-mixer-1
       - allwinner,sun50i-h6-de3-mixer-0
+      - allwinner,sun50i-h616-de33-mixer-0
 
-  reg:
-    maxItems: 1
+  reg: true
+
+  reg-names: true
 
   clocks:
     items:

@@ -61,6 +63,34 @@ properties:
     required:
       - port@1
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - allwinner,sun50i-h616-de33-mixer-0
+    then:
+      properties:
+        reg:
+          description: |
+            Registers for controlling individual layers of the display
+            engine (layers), global control (top), and display blending
+            control (display). Names are from Allwinner BSP kernel.
+          maxItems: 3
+        reg-names:
+          items:
+            - const: layers
+            - const: top
+            - const: display
+      required:
+        - reg-names
+
+    else:
+      properties:
+        reg:
+          maxItems: 1
+
 required:
   - compatible
   - reg

-- 
2.49.0